Visual Illusions Capture Imagination

The 2014 winners of the Best Illusion of the Year Contest were announced this past Sunday. Hosted yearly since 2005 by the Neural Correlate Society, the contest celebrates “the ingenuity and creativity of the world’s premier visual illusion research community.”

Here is the Illusion of the Year 2014: The Dynamic Ebbinghaus takes a classic, static size illusion and transforms it into a dynamic, moving display. A central circle, which stays the same size, appears to change size when it is surrounded by a set of circles that grow and shrink over time. Interestingly, this effect is relatively weak when looking directly at a stationary central circle. But if you look away from the central circle or move your eyes, or if the entire stimulus move across the screen, then the illusory effect is surprisingly strong — at least twice as large as the classic, static Ebbinghaus illusion.

The Dynamic Ebbinghaus

When we look at two pictures that are physically the same, they usually look the same. When they are different, they look different. Our illusions show the opposite: two images that are different but look the same – those are called “metamers”; – and two images that are identical but look different – we call those “anti-metamers.” Our main illusion mixes the two: it shows three images, two of which match with a third one mismatching. Viewers see one image as odd, but it’s one of the two identical images they see as different, an illusion we call “false pop out.”

This is an anamorphic illusion. It begins as a normal photograph and then is tilted backwards and forwards to create opposite vanishing points. The tilting distorts the shape of the head and facial features to create the illusion of an actual age progression and regression. For the age progression the top half of the head narrows, and the bottom half expands creating a more mature look. For the age regression, the opposite happens. The head and ears enlarge and the lower face narrows giving them a smaller nose, chin and neck, which results in a realistic childlike appearance.

In the world of optical illusions, the terms ‘autokinetic illusion’ or ‘apparent motion’ are used to describe the convincing appearance of movement in a picture that the viewer knows to be static. We would like to present here a new kind of autokinetic illusions involving expansive motion created by/with parallel arrangements of cuspidate (needle-shaped) lines.

In this illusion a rectangle moving at a constant speed in front of stripes generates apparent reverse motion. This apparent motion is similar to the action of a neck when the pigeon walks.
Well-known kickback illusion also appears to move reversely in a moment. For the case of the kickback illusion, the width of stripes is thin. However, for the case of the pigeon-neck illusion, the width of stripes is thicker. Thus the conditions between them are different, and so the pigeon-neck illusion is new.